CDMA reception apparatus and received signal power measuring apparatus in CDMA mobile communication system

ABSTRACT

In a CDMA reception apparatus, averaging part for averaging at least one of vector, amplitude and power of received signal of a plurality of transmit power control sections is provided. Further, propagation path variation estimator for estimating a propagation path variation of the present transmit power control section from respective transmit power control sections in the past to obtain a propagation path variation estimation value and propagation path variation correction part (multiplier) for correcting by the propagation path variation estimation value are further provided, wherein the averaging part averages at least one of vector, amplitude and power of received signal of the plurality of transmit power control sections corrected by the propagation path variation correction part (multiplier). With this configuration, the measurement accuracy is improved by measuring received signal power using a plurality of slots including past slots, resulting in more accurate transmit power control.

This application is based on Patent Application No. 11-206789 (1999)filed Jul. 21, 1999 in Japan, the contents of which are incorporatedhereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mobile communication receptionapparatus in mobile communications applied with digital radiocommunication system, particularly with CDMA (code division multipleaccess) system, more specifically to received signal power measurementfor transmit power control.

2. Description of the Prior Art

An example of relationship between flow of transmit power control ofCDMA mobile communication system by the prior art and radio slotconfiguration is schematically shown in FIG. 1.

As shown in FIG. 1, 1) received signal power measurement is performedfor each transmit power control section (hereinafter referred to as“slot”), 2) the measurement result is subjected to a divisioncalculation using a measurement result of noise interference power toobtain a received SNIR (signal power to interference power ratio), thereceived SNIR is compared with a reference SNIR, 4) a transmit powercontrol bit is transmitted designating a transmit power controlindicator of the received side channel, so that when the comparisonresult exceeds the reference SNIR, a base station transmit power isdecreased, or when the comparison result is below the reference SNIR,the base station transmit power is increased.

As shown in FIG. 1, in the traffic channel, there exists not only afixed transmit part (shaded in FIG. 1) in which the number of transmitbits is unchanged, but also a variable transmit part in which thetransmit bit number is successively changed according to a change ininformation speed of transmitted data, when there is no data, transmitis stopped. In this case, the fixed transmit part is applied to receivedsignal power measurement.

As shown above, received signal power measurement in a CDMA receptionapparatus is performed using a fixed transmit part, however, there is aproblem that when signal power of the fixed transmit part is small,measurement accuracy of received signal power is deteriorated, andtransmit power control is not performed with good accuracy.

As described above, accuracy degradation of transmit power control hasresulted in an increase in transmit power and deterioration of channelcapacity.

SUMMARY OF THE INVENTION

An object of the present invention is to improve the measurementaccuracy by measuring received signal power using a plurality of slotsincluding past slots, thereby performing even more accurate transmitpower control. With this, the object is to achieve improvement ofcommunication quality, reduction of transmit power and increase ofcapacity.

Further, when using received signals of a plurality of slots includingpast slots in measurement of received power, measurement accuracy isimproved when the traveling speed of the mobile terminal is slow sincethe propagation path variation is small, however, when the travelingspeed of the mobile terminal is high, since the propagation pathvariation is large, there is a possibility that the measurement accuracyis deteriorated. As shown, the number of slots used for received signalpower measurement suitable for accuracy is varied with the travelingspeed. Further, to use signals of past slots for measurement of receivedsignal power, by averaging a result of multiplying a change in variationof propagation path and a change in transmit power changed by transmitpower control from a past to present, measurement accuracy can beimproved. In particular, other than a dedicated traffic channel which isapplied to transmit power control, in a downlink where channel receptionof a common channel of fixed transmit power is possible such as a pilotchannel, it is possible to estimate propagation path variation using thecommon channel. However, as there is a variation in propagation path oras estimation accuracy of change in transmit power is degraded, theremay be a case where received signal power measurement accuracy isdeteriorated by using past slot signals for measurement. In particular,when the fixed transmit part in the above-described slot is large, sincemany measurable received signals are present in 1 slot, the accuracy isbetter than averaging many slots, when the number of slots to beaveraged is small, or in some case, when there is only one slot to beaveraged. Still further, also in a downlink, when the propagation pathof common channel is different from the propagation path of a dedicatedtraffic channel such as in the case where a transmit adaptive arrayantenna is applied to the transmit side, that is, the base station side,propagation path estimation is difficult, and there may be a case wherethe accuracy is deteriorated by using a plurality of slots of the past.As shown, the optimum number of slots used for received signal powermeasurement is changed.

Then, an object of the present invention is to achieve received signalpower measurement suitable for respective systems and propagationenvironments by changing the number of averaging slots according totraveling speed, channel format, and system details without changing thealgorithm, improve the measurement accuracy, achieve a reduction oftransmit power and an increase of capacity, and suppress complexity ofreception apparatus, especially complexity of mobile communicationterminal apparatus.

In accordance with the present invention which attains the aboveobjects, there is provided a received signal power measurement using aplurality of past slots for improving measurement accuracy of receivedsignal power, making a transmit power control highly accurate, therebyenabling high communication quality, reduction of transmit power, andincreased capacity. Further, by changing the number of averaging slotsaccording to the traveling speed, channel format, and system details, itis possible to perform received signal power measurement suitable forrespective environments without changing the algorithm, thereby reducingthe transmit power, increasing the capacity and suppressing the size ofthe reception apparatus.

The CDMA reception apparatus and received signal power measurementmethod described in respective claims are as what follows.

In a first aspect of the present invention, there is provided a CDMAreception apparatus comprising:

-   -   propagation path variation estimation means for estimating a        propagation path variation in a present transmit power control        section from respective transmit power control sections in the        past to obtain a propagation path variation estimation value;    -   propagation path variation correction means for correcting at        least one of vector, amplitude and/or power of a received signal        of the plurality of transmit power control sections with the        propagation path variation estimation value obtained by the        propagation path variation estimation means; and    -   averaging means for averaging at least one of vector, amplitude        and/or power of received signal of the plurality of transmit        power control sections corrected by the propagation path        variation correction means.

According to the present invention, by using a plurality of slotsincluding past slots for received signal power measurement, measurementaccuracy of received signal power can be improved. Further, when usingthe past slots for received signal power measurement, by making acorrection using an estimation value of propagation path variation fromthe past slot timing up to the present timing, it is possible to performreceived signal power measurement more accurately.

In a second aspect of the present invention, there is provided a CDMAreception apparatus comprising:

-   -   transmit power changing amount estimation means for estimating a        changing amount of transmit power of a communication partner        station varied by transmit power control in the present transmit        power control section from respective transmit power control        sections in the past;    -   transmit power changing amount correction means for correcting        at least one of vector, amplitude and/or power of a received        signal of the plurality of transmit power control sections with        the transmit power changing amount estimation value obtained by        the transmit power changing amount estimation means; and    -   averaging means for averaging at least one of vector, amplitude        and/or power of received signal of the plurality of transmit        power control sections corrected by the transmit power changing        amount correction means.

According to the present invention, when using the past slots forreceived signal power measurement, by correcting using a change amountof transmit power from the past slot timing up to the present timing, itis possible to perform received signal power measurement moreaccurately.

The averaging means may be provided with vector addition means forperforming vector addition;

-   -   division means for dividing a vector added by the vector        addition means with a number of vectors added; and    -   means for converting vector divided by the division means into a        power.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging byvector addition, it is possible to suppress effects of noise andmeasurement accuracy of received signal power can be improved.

The averaging means may be provided with

-   -   amplitude addition means for performing amplitude addition;    -   division means for dividing an amplitude added by the amplitude        addition means with a number of amplitudes added; and    -   means for converting amplitude divided by the division means        into a power.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging byamplitude addition, simpler and more accurate averaging is possible.

The averaging means may be provided with power addition means forperforming power addition;

-   -   division means for dividing a power added by the power addition        means with a number of powers added.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging bypower addition, simpler and more accurate averaging is possible.

The propagation path variation estimation means may estimate apropagation path variation using a channel not performing transmit powercontrol.

According to the present invention, when estimating propagation pathvariation, by using a channel not performing transmit power control (forexample, common channel or the like), propagation path variationestimation of high accuracy can be performed.

The transmit power changing amount estimation means may estimate atransmit power changing amount using a transmit power control indicatortransmitted from own station.

According to the present invention, when estimating a transmit powerchanging amount, by using a transmit power control indicator (forexample, transmit power control bit) transmitted from its own station, ahigh accuracy transmit power changing amount estimation is possible.

The averaging means may further comprise averaging section setting meansfor setting an averaging section.

According to the present invention, by selecting an appropriateaveraging section according to the system details and propagationenvironment, it is possible to perform measurement of received signalpower suited to environment without changing the algorithm.

The averaging section setting means may comprise:

-   -   means for setting the averaging section to a small section, when        performing communication by a channel of which a power allocated        to a signal subjected to received signal power measurement        existing in each transmit power control section is high; and    -   means for setting the averaging section to a large section, when        performing communication by a channel of which a power allocated        to a signal subjected to received signal power measurement        existing in each transmit power control section is small.

According to the present invention, depending on the power of receivedsignal subjected to received signal power measurement existing betweenrespective transmit power control sections, when the power is high, theaveraging section is reduced to decrease effects of error of pastreceived signals, or when the power is low, the averaging section isincreased to reduce effects of measurement error due to noise, it ispossible to set an averaging section for optimum measurement accuracy.

The averaging section setting means may comprise:

-   -   means for setting the averaging section to a large section, when        a partner transmit station performs transmit power control,        there is a channel other than channel transmitting to the        received station and transmitting a channel not performing        transmit power control with the same antenna and directivity,        and propagation path variation estimation using the channel not        performing transmit power control is possible; and    -   means for setting the averaging section to a small section, when        a partner transmit station performs transmit power control,        there is not a channel other than channel transmitting to the        reception station and transmitting a channel not performing        transmit power control with the same antenna and directivity, or        even when transmitting but not performing transmit power        control, and propagation path variation estimation using the        channel not performing transmit power control is not possible.

According to the present invention, when estimation of propagation pathvariation is impossible, since when signals of past slots are used,received power measurement accuracy is deteriorated due to effects ofpropagation path variation, it is possible to reduce the averagingsection and enhance the measurement accuracy.

The averaging section setting means may comprise:

-   -   traveling speed detection means for detecting a relative        traveling speed between a communication partner station and own        station; and    -   means for setting the averaging section to a small section when        the detected traveling speed is large, and for setting the        averaging section to a large section when the detected traveling        speed is small.

According to the present invention, when a traveling speed is highbetween the opposite transmit station and the own station, by decreasingthe averaging section, it is possible to prevent deterioration ofreceived signal power measurement accuracy due to propagation pathvariation.

In a third aspect of the present invention, there is provided a receivedsignal power measurement method of a CDMA reception apparatus,comprising:

-   -   a propagation path variation estimation step for estimating a        propagation path variation in a present transmit power control        section from respective transmit power control sections in the        past to obtain a propagation path variation estimation value;    -   a propagation path variation correction step for correcting at        least one of vector, amplitude and/or power of a received signal        of the plurality of transmit power control sections with the        propagation path variation estimation value obtained by the        propagation path variation estimation step; and    -   an averaging step for averaging at least one of vector,        amplitude and/or power of received signal of the plurality of        transmit power control sections corrected by the propagation        path variation correction step.

According to the present invention, by using a plurality of slotsincluding past slots for received signal power measurement, receivedsignal power measurement accuracy can be improved. Further, when usingpast slots for received signal power measurement, by correcting using anestimation amount of propagation path variation from the past slottiming up to the present timing, it is possible to perform receivedsignal power measurement more accurately.

In a fourth aspect of the present invention, there is provided areceived signal power measurement method of a CDMA reception apparatus,comprising:

-   -   a transmit power changing amount estimation step for estimating        a changing amount of transmit power of a communication partner        station varied by transmit power control in the present transmit        power control section from respective transmit power control        sections in the past;    -   a transmit power changing amount correction step for correcting        at least one of vector, amplitude and/or power of a received        signal of the plurality of transmit power control sections with        the transmit power changing amount estimation value obtained by        the transmit power changing amount estimation step; and    -   an averaging step for averaging at least one of vector,        amplitude and/or power of received signal of the plurality of        transmit power control sections corrected by the transmit power        changing amount correction step.

According to the present invention, when using past slots for receivedsignal power measurement, by correcting using an estimation value ofchange amount of transmit power from the past slot timing up to thepresent timing, it is possible to perform received signal powermeasurement more accurately.

The averaging step may be provided with a vector addition step forperforming vector addition;

-   -   a division step for dividing a vector added by the vector        addition step with a number of vectors added; and    -   a step for converting vector divided by the division step into a        power.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging byvector addition, it is possible to suppress effects of noise andmeasurement accuracy of received signal power can be improved.

The averaging step may be provided with an amplitude addition step forperforming amplitude addition;

-   -   a division step for dividing an amplitude added by the amplitude        addition step with a number of amplitudes added; and    -   a step for converting amplitude divided by the division step        into a power.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging byamplitude addition, simpler and more accurate averaging is possible.

The averaging step may be provided with a step for performing poweraddition;

-   -   a division step for dividing a power added by the power addition        step with a number of powers added.

According to the present invention, when averaging received signals of aplurality of slots including past slots, by performing averaging bypower addition, simpler and more accurate averaging is possible.

The propagation path variation estimation step may estimate apropagation path variation using a channel not performing transmit powercontrol.

According to the present invention, when estimating propagation pathvariation, by using a channel not performing transmit power control (forexample, common channel or the like), propagation path variationestimation of high accuracy can be performed.

The transmit power changing amount estimation step may estimate atransmit power changing amount using a transmit power control indicatortransmitted from own station.

According to the present invention, when estimating a transmit powerchanging amount, by using a transmit power control indicator (forexample, transmit power control bit) transmitted from its own station, ahigh accuracy transmit power changing amount estimation is possible.

The averaging step may further comprise an averaging section settingstep for setting an averaging section.

According to the present invention, by selecting an appropriateaveraging section according to the system details and propagationenvironment, it is possible to perform measurement of received signalpower suited to environment without changing the algorithm.

The averaging section setting step may comprise:

-   -   a step for setting the averaging section to a small section,        when performing communication by a channel of which a power        allocated to a signal subjected to received signal power        measurement existing in each transmit power control section is        high; and    -   a step for setting the averaging section to a large section,        when performing communication by a channel of which a power        allocated to a signal subjected to received signal power        measurement existing in each transmit power control section is        small.

According to the present invention, depending on the power of receivedsignal subjected to received signal power measurement existing betweenrespective transmit power control sections, when the power is high, theaveraging section is reduced to decrease effects of error of pastreceived signals, or when the power is low, the averaging section isincreased to reduce effects of measurement error due to noise, it ispossible to set an averaging section for optimum measurement accuracy.

The averaging section setting step may comprise:

-   -   a step for setting the averaging section to a large section,        when a partner transmit station performs transmit power control,        there is a channel other than channel transmitting to the        reception station and transmitting a channel not performing        transmit power control with the same antenna and directivity,        and propagation path variation estimation using the channel not        performing transmit power control is possible; and    -   a step for setting the averaging section to a small section,        when a partner transmit station performs transmit power control,        there is not a channel other than channel transmitting to the        reception station and transmitting a channel not performing        transmit power control with the same antenna and directivity, or        even when transmitting but not performing transmit power        control, and propagation path variation estimation using the        channel not performing transmit power control is not possible.

According to the present invention, when estimation of propagation pathvariation is impossible, since when signals of past slots are used,received power measurement accuracy is deteriorated due to effects ofpropagation path variation, it is possible to reduce the averagingsection and enhance the measurement accuracy.

The averaging section setting step may comprise:

-   -   a step for detecting a relative traveling speed between a        communication partner station and own station; and    -   a step for setting the averaging section to a small section when        the detected traveling speed is large, and for setting the        averaging section to a large section when the detected traveling        speed is small.

According to the present invention, when a traveling speed is highbetween the opposite transmit station and the own station, by decreasingthe averaging section, it is possible to prevent deterioration ofreceived signal power measurement accuracy due to propagation pathvariation.

The above and other objects, effects, features and advantages of thepresent invention will become more apparent from the followingdescription of embodiments thereof taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing an example of relationshipbetween flow of transmit power control of a prior art CDMA mobilecommunication system and radio slot configuration;

FIG. 2 is a block diagram showing an example of construction ofreception apparatus in the CDMA mobile terminal in an embodiment 1 ofthe present invention;

FIG. 3 is a block diagram showing an example of construction of areceived SNIR measurement part 208 in FIG. 2;

FIG. 4 is a diagram showing the relationship of FIGS. 4A and 4B.

FIG. 4A is a block diagram showing an example of construction of areceived signal power measurement part 304 in FIG. 3;

FIG. 4B is a block diagram showing an example of construction of areceived signal power measurement part 304 in FIG. 3;

FIG. 5 is a block diagram showing an example of construction of apropagation path estimation part to which the present invention isapplied;

FIG. 6 is a block diagram showing an example of construction of atransmit power changing amount estimation part to which the presentinvention is applied;

FIG. 7 is a block diagram showing an example of construction of areceived signal power measurement part in an embodiment 2 of the presentinvention;

FIG. 8 is a flow chart for explaining a setting method of averagingsection in the embodiment 1 of the present invention;

FIG. 9 is a flow chart for explaining a setting method of a forgettingfactor α in embodiment 2 of the present invention; and

FIG. 10 is a flow chart showing an example of operation of a receivedsignal power measurement part.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be describedwith reference to the drawings.

The present invention can be applied to a base station receptionapparatus as an uplink receiver, however, because the above-describedestimation of propagation path variation can be performed by a channelnot performing the transmit power control, an example of downlinkreceiver, that is, a case where a reception apparatus of a mobilecommunication terminal is used will be described as the followingembodiment.

Embodiment 1

FIG. 2 is a block diagram showing an example of construction of areception apparatus in a CDMA mobile terminal in the embodiment 1 of thepresent invention.

A reception apparatus 200 includes a reception radio part 202, adespreader 204, a received data demodulator 206, a received SNIRmeasurement part 208 and a SNIR comparator 212.

The reception radio part 202 receives a radio signal transmitted from aradio base station, performs frequency conversion and filtering, andoutputs a baseband signal.

In the despreader 204, despreading of the baseband signal is performed,and a received despread signal is outputted to the received data decoder206 and a received SNIR calculator 208.

In the received data demodulator 206, RAKE combining, error correctiondecoding and the like are performed to demodulate the received data. Atthe same time, the received despread signal is inputted to the receivedSNIR measurement part 208 to output a received SNIR at every slot, acomparison of the outputted value with a target SNIR 210 is performed inthe SNIR comparator 212, according to the comparison result, a transmitpower control bit 214 (transmit power control indicator) to betransmitted is outputted.

FIG. 3 is a block diagram showing an example of construction of thereceived SNIR measurement part 208 in FIG. 2.

The received SNIR measurement part 208 comprises a received signal powermeasurement part 304, a noise interference power measurement part 306and a divider 308.

The received despread signal 302 outputted from the despreader 204 isinputted respectively to the received signal power measurement part 304and the received noise interference power measurement part 306, and therespective measurement results A and B are divided in the divider 308 toobtain a received SNIR 310.

FIGS. 4A and 4B is a block diagram showing an example of construction ofthe received signal power measurement part 304 in FIG. 3.

Here, in FIGS. 4A and 4B, alphabet n shows a present number of slots,and K a maximum number of received signal slots for performingaveraging.

The received signal power measurement part 304 includes a RAKE combiner404, a delayer 406, a propagation path estimator 407, a transmit powerchanging amount estimator 409, an averaging part 412, a received signalpower calculator 414, and an averaging section setting part 416.

The received despread signal 402 of fixed transmit part of the dedicatedtraffic channel is RAKE combined by the RAKE combiner 404, and anaverage value of received signal of each slot is stored in the delayer406. The stored value can be any of vector, amplitude and/or power.Received signal of past slots stored in the delayer 406 is multiplied bythe multiplier with the propagation path variation estimation value 408of the past slot timing and the present timing generated in thepropagation path estimator 407. Further, after multiplication by themultiplier with the estimation value 410 of changing amount of transmitpower by transmit power control of the past slot timing and the presenttiming, averaging is performed along with the present slot in theaveraging part 412. Still further, when the stored value is vector oramplitude, it is converted into power by the received signal powercalculator 414, and outputted as received signal power.

In the averaging section setting part 416, as will be described later,the averaging section is appropriately set according to the propagationenvironment and environment of the system in communication.

FIG. 10 is a flow chart showing an example of operation of the receivedsignal power measurement part 304.

First, received despread signal 402 of fixed transmit part of adedicated traffic channel is RAKE combined by the RAKE combiner 404(step S1002).

Next, an average value of received signal of each slot is stored in thedelayer 406 (step S1004). The stored value can be any of vector,amplitude and/or power.

Next, in the propagation path estimator 407, propagation path variationin the present transmit control section is estimated from information ofrespective past transmit power control sections to obtain a propagationpath variation estimation value 408 (step S1006).

Next, at least one of vector, amplitude and/or power of received signalsof a plurality of transmit power control sections is corrected bymultiplying using the propagation path variation estimation value 408obtained by the propagation path estimator 407 (step S1008).

Next, in the transmit power changing amount estimator 409, a changingamount of transmit power changed by transmit power control of thecommunication partner station in the present transmit power controlsection is estimated from information of past respective transmit powercontrol sections (for example, past transmit power control bit datastored in any of storage apparatus (not shown) in the receptionapparatus) to obtain a transmit power changing amount estimation value410 (step S1010).

Next, at least one of vector, amplitude and/or power of received signalsof a plurality of transmit power control sections is corrected bymultiplying using the transmit power changing amount estimation value410 obtained by the transmit power changing amount estimator 409 (stepS1012).

Next, in the averaging part 412, at least one of vector, amplitudeand/or power of the corrected received signals of the plurality oftransmit power control sections is averaged (step S1014).

Next, an averaging section setting method in the averaging sectionsetting part 416 will be described with reference to FIG. 8.

First, for example, the amount of power allocated to the fixed transmitpart of signal from the communication partner station corresponding tothe shaded part in FIG. 1 is judged from the channel format incommunication (step S802), setting is made so that the averaging sectionis decreased when the power is large (step S804), or the averagingsection is increased when the power is small (step S806). Alternatively,a judgment is made from informed information from the system as towhether or not there is a common channel transmitted without performingtransmit power with the same antenna and directivity and propagationpath estimation is possible (step S808), when propagation pathestimation is possible the averaging section is increased (step S810),or when propagation path estimation is impossible the averaging sectionis decreased (step S812). On the other hand, when propagation pathestimation is not performed, traveling speed of the traveling machine isdetected (step S814), when the traveling speed is high and variation ofpropagation path is large, the averaging section is set small (stepS816), or when the traveling speed is low and variation of propagationpath is small, the averaging section is set large (step S818).

FIG. 5 is a block diagram showing an example of construction of thepropagation path estimator 407 in FIGS. 4A and 4B.

Here, alphabet n in FIG. 5 shows a present slot number, and K a slotnumber of largest received signal for averaging.

The propagation path estimator 407 includes a delayer 504 and a divider506.

In the propagation path estimator 407, amplitude of a received signal502 after RAKE combining of the common channel not performing transmitpower control is stored in the delayer 504 for each slot, by performingdivision calculation A/B of the received signal A of the present slotand the received signal B of respective past slot in the divider 506,thereby outputting a propagation path variation estimation value 508 ofthe present slot from the past respective slots.

FIG. 6 is a block diagram showing an example of construction of thetransmit power changing amount estimator 409 in FIGS. 4A and 4B.

Here, alphabet n in FIG. 6 shows a present slot number, and K a slotnumber of largest received signal for averaging.

The transmit power changing amount estimator 409 includes a transmitpower changing amount converter 604 and a delayer 606.

The transmit power changing amount estimator 409 estimates a changingamount of transmit power from a radio base station from the transmitpower control bit 602 transmitted by the mobile terminal to the radiobase station.

First, in the transmit power changing amount converter 604, the transmitpower control bit 602 transmitted from the mobile terminal is convertedinto a transmit power changing amount to obtain a transmit power controlestimation value 608. Next, output after changing is multiplied with thetransmit power changing amount from each slot timing up to the presentstored in the delayer 606 to obtain a new transmit power controlestimation value 608.

Embodiment 2

In the following, an embodiment 2 according to the present inventionwill be described with reference to FIG. 7.

FIG. 7 is a block diagram showing an example of construction of areceived signal power measurement part in the embodiment 2 of thepresent invention. In the receiver, construction other than the receivedsignal power measurement part is similar to that in the embodiment 1.

A received signal power measurement part 700 in the embodiment 2includes an a multiplier 702, a delayer 704, a propagation pathestimator 705, a transmit power changing amount estimator 707, areceived signal power calculator 710, an averaging section setting part712, a RAKE combiner 716 and a 1−α multiplier 718.

The delayer 704, the propagation path estimator 705, the transmit powerchanging amount estimator 707, the received signal power calculator 710,the averaging section setting part 712, and the RAKE combiner 716 havethe same functions as those described in FIGS. 4 to 9, and the αmultiplier 702 and the 1−α multiplier respectively have functions formultiplying the input with α or 1−α.

The received signal power measurement part 700 has a form of a feedbacktype filter which performs averaging of the received signal of thepresent slot and the received signal of the past slot using a forgettingfactor α702. That is, for the received signal of the past slot stored inthe delayer 704, after multiplication with the propagation pathvariation estimation value 706 between 1 slot previous timing and thepresent timing and the transmit power changing amount estimation value708, it is multiplied with the forgetting factor α in the α multiplier702 to perform averaging with the received signal of the present slot.In the received signal power calculator 710, a received signal power iscalculated from received signal after averaging and the result isoutputted. On the other hand, received signal after averaging is storedagain in the delayer 704. In the averaging section setting part 712, αis appropriately set according to the propagation environment anddetails of the system in communication.

Next, setting method of the forgetting factor α will be described withreference to FIG. 9.

First, for example, the amount of power allocated to the fixed transmitpart of signal from the communication partner station corresponding tothe shaded part in FIG. 1 is judged from the channel format incommunication (step S902), setting is made so that α is decreased whenthe power is large (step S904), or a is increased when the power issmall (step S906). Alternatively, a judgment is made from informedinformation from the system as to whether or not there is a commonchannel transmitted without performing transmit power with the sameantenna and directivity and propagation path estimation is possible(step S908), when propagation path estimation is possible α is increased(step S910), or when propagation path estimation is impossible α isdecreased (step S912). On the other hand, when propagation pathestimation is not performed, traveling speed of the traveling machine isdetected (step S914), when the traveling speed is high and variation ofpropagation path is large, α is set small (step S916), or when thetraveling speed is low and variation of propagation path is small, α isset large (step S918).

EFFECTS OF THE INVENTION Effects of Embodiment 1

As shown in FIG. 3, by obtaining the received signal power by averaginga plurality of slots including past slots, even when the fixed transmitpart included in 1 slot is small, the effective measurement bit numbercan be increased, and received power measurement of higher accuracy canbe performed.

Further, for the above-shown averaging of a plurality of slots, when acommon channel cannot be used for estimation, or when the propagationpath fixed transmit part is large, the number of slots for averaging isdecreased, or depending on the case, only the present slot is used,averaging by an appropriate averaging slot number can be performedwithout changing the construction of the receiver and measurementalgorithm, whereby high quality communication, reduction of transmitpower, and increased channel capacity can be achieved, and complexity ofthe mobile terminal can be suppressed.

Effects of embodiment 2

With the construction as in the embodiment 2, the same effects as shownin embodiment 1 can be obtained, and averaging of the received signalpower is performed by weighting average using the forgetting factor α,buffers such as delayer for storing past received signals can bereduced.

For example, in embodiment 1, averaging of a plurality of slots iscalculated by Formula 1 shown below.averagedR _(—) n=(R _(—) n+R _(—) {n−1}+R{n−2}+R _(—) {n−3})/4  [FORMULA1]

The formula (1) is a formula for averaging using past 4 slots, in whichR_n shows a received power value of n'th slot. Further, for simplicityof description, cancel due to variation is not considered.

While, an ordinary averaging using FIR filter as shown above isperformed in embodiment 1, averaging in embodiment 2 is represented byaveragedR _(—) n=Rn*+averagedR _(—) {n−1}*(1−α)  [FORMULA 2]and exponential weighted averaging (averaging using IIR filter) isperformed using the forgetting factor α. For example, when it is assumedas α=0.25, the same averaging effect as averaging of about 4 slots canbe obtained. Therefore, by performing such exponential weightedaveraging, only one previous value (in the above formula, averagedR_(n−1)) of past received power value may be stored, thereby reducingthe calculation amount.

Further, the propagation path variation estimation value and thetransmit power changing amount estimation value are also calculation forimmediately 1 slot previous values, and the calculation amount can bereduced.

Still further, when the effect of the value using received signals ofpast slots is to be changed, it can be achieved by changing the factorα.

The present invention has been described in detail with respect tovarious embodiments, and it will now be apparent from the foregoing tothose skilled in the art that changes and modifications may be madewithout departing from the invention in its broader aspects, and it isthe intention, therefore, in the appended claims to cover all suchchanges and modifications as fall within the true spirit of theinvention.

1. A CDMA reception apparatus comprising: propagation path variationestimation means for estimating propagation path variations betweenrespective prior transmit power control sections and a current transmitpower control section to obtain propagation path variation estimationvalues, wherein each of the propagation path variation estimation valuesis obtained by estimating a propagation path variation between adifferent corresponding prior transmit power control section and thecurrent transmit power control section; propagation path variationcorrection means for generating a plurality of corrected products, eachcorrected product obtained by multiplying at least one of vector,amplitude and/or power of a received signal of the differentcorresponding prior transmit power control section by said propagationpath variation estimation value obtained by estimating the propagationpath variation between the different corresponding prior transmit powercontrol section and the current transmit power control section; andaveraging means for averaging the plurality of corrected productsincluding averaging section setting means for setting an averagingsection, wherein said averaging section setting means comprises: meansfor setting said averaging section smaller than the present averagingsection when performing communication by a channel in each transmitpower control section, in which power of said channel allocated to asignal subjected to received signal power measurement is higher than apredetermined value; and means for setting said averaging section largerthan the present averaging section when performing communication by achannel in each transmit power control section, in which power of saidchannel allocated to a signal subjected to received signal powermeasurement is smaller than the predetermined value.
 2. The CDMAreception apparatus as claimed in claim 1, wherein said averagingsection setting means comprises: means for setting said averagingsection larger than the present averaging section when a partnertransmit station transmits a channel whose power is controlled andanother channel whose power is not controlled with the same antenna anddirectivity, and said channel whose transmit power is not controlledtransmits a pilot signal; and means for setting said averaging sectionsmaller than the present averaging section when a partner transmitstation does not transmit said channel whose power is controlled andanother channel whose power is not controlled with the same antenna anddirectivity, or said channel whose transmit power is not controlled doesnot transmit the pilot signal.
 3. The CDMA reception apparatus asclaimed in claim 1, wherein said averaging section setting meanscomprises: traveling speed detection means for detecting a relativetraveling speed between a communication partner station and own station;and means for setting said averaging section smaller than the presentaveraging section when said detected traveling speed is larger than apredetermined value, and for setting said averaging section to largerthan the present averaging section when said detected traveling speed issmaller than the predetermined value.
 4. A received signal powermeasurement method of a CDMA reception apparatus, comprising: apropagation path variation estimation step for estimating propagationpath variations between respective prior transmit power control sectionsand a current transmit power control section to obtain propagation pathvariation estimation values, wherein each of the propagation pathvariation estimation values is obtained by estimating a propagation pathvariation between a different corresponding prior transmit power controlsection and the current transmit power control section; a propagationpath variation correction step for generating a plurality of correctedproducts, each corrected product obtained by multiplying at least one ofvector, amplitude and/or power of a received signal of the differentcorresponding prior transmit power control section and the currenttransmit power control section; and an averaging step for averaging theplurality of corrected products including an averaging section settingstep for setting an averaging section, wherein said averaging sectionsetting step comprises: a step for setting said averaging sectionsmaller than the present averaging section when performing communicationby a channel in each transmit power control section, in which power ofsaid channel allocated to a signal subjected to received signal powermeasurement is higher than a predetermined value; and a step for settingsaid averaging section larger than the present averaging section whenperforming communication by a channel in each transmit power controlsection, in which power of said channel allocated to a signal subjectedto received signal power measurement is smaller than the predeterminedvalue.
 5. The received signal power measurement method as claimed inclaim 4, wherein said averaging section setting step comprises: a stepfor setting said averaging section larger than the present averagingsection when a partner transmit station transmits a channel whose poweris controlled and another channel whose power is not controlled with thesame antenna and directivity, and said channel whose transmit power isnot controlled transmits a pilot signal; and a step for setting saidaveraging section smaller than the present averaging section when apartner transmit station does not transmit said channel whose power iscontrolled and another channel whose power is not controlled with thesame antenna and directivity, or said channel whose transmit power isnot controlled does not transmit the pilot signal.
 6. The receivedsignal power measurement method as claimed in claim 4, wherein saidaveraging section setting step comprises: a step for detecting arelative traveling speed between a communication partner station and ownstation; and a step for setting said averaging section smaller than thepresent averaging section when said detected traveling speed is largerthan a predetermined value, and for setting said averaging sectionlarger than the present averaging section when said detected travelingspeed is smaller than the predetermined value.
 7. A CDMA receptionapparatus comprising: transmit power changing amount estimation meansfor estimating changing amounts of transmit power of a communicationpartner station varied by transmit power control between respectiveprior transmit power control sections and a current transmit powercontrol section to obtain transmit power changing amount estimationvalues, wherein each of the transmit power changing amount estimationvalues is obtained by estimating a transmit power changing amountbetween a different corresponding prior transmit power control sectionand the current transmit power control section; transmit power changingamount correction means for generating a plurality of correctedproducts, each corrected product obtained by multiplying at least one ofvector, amplitude and/or power of a received signal of the differentcorresponding prior transmit power control section by said transmitpower changing amount estimation value obtained by estimating thetransmit power changing amount between the different corresponding priortransmit power control section and the current transmit power controlsection; and averaging means for averaging the plurality of correctedproducts, including averaging section setting means for setting anaveraging section, wherein said averaging section setting meanscomprises: means for setting said averaging section smaller than thepresent averaging section when performing communication by a channel ineach transmit power control section in which power of said channelallocated to a signal subjected to received signal power measurement ishigher than a predetermined value; and means for setting said averagingsection larger than the present averaging section when performingcommunication by a channel in each transmit power control section inwhich power of said channel allocated to a signal subjected to receivedsignal power measurement is smaller than the predetermined value.
 8. TheCDMA reception apparatus as claimed in claim 7, wherein said averagingsection setting means comprises: means for setting said averagingsection larger than the present averaging section when a partnertransmit station transmits a channel whose power is controlled andanother channel whose power is not controlled with the same antenna anddirectivity, and said channel whose transmit power is not controlledtransmits a pilot signal; and means for setting said averaging sectionsmaller than the present averaging section when a partner transmitstation does not transmit said channel whose power is controlled andanother channel whose power is not controlled with the same antenna anddirectivity, or said channel whose transmit power is not controlled doesnot transmit the pilot signal.
 9. The CDMA reception apparatus asclaimed in claim 7, wherein said averaging section setting meanscomprises: traveling speed detection means for detecting a relativetraveling speed between a communication partner station and own station;and means for setting said averaging section smaller than the presentaveraging section when said detected traveling speed is larger than apredetermined value, and for setting said averaging section to largerthan the present averaging section when said detected traveling speed issmaller than the predetermined value.
 10. A received signal powermeasurement method of a CDMA reception apparatus, comprising: a transmitpower changing amount estimation step for estimating changing amounts oftransmit power of a communication partner station varied by transmitpower control between respective prior transmit power control sectionsand a current transmit power control section to obtain transmit powerchanging amount estimation values, wherein each of the transmit powerchanging amount estimation values is obtained by estimating a transmitpower changing amount between a different corresponding prior transmitpower control section and the current transmit power control section; atransmit power changing amount correction step for generating aplurality of corrected products, each corrected product obtained bymultiplying at least one of vector, amplitude and/or power of a receivedsignal of the different corresponding prior transmit power controlsection by said transmit power changing amount estimation value obtainedby estimating the transmit power changing amount between differentcorresponding prior transmit power control section and the currenttransmit power control section; and an averaging step for averaging theplurality of corrected products, including an averaging section settingstep for setting an averaging section, wherein said averaging sectionsetting step comprises: a step for setting said averaging sectionsmaller than the present averaging section when performing communicationby a channel in each transmit power control section, in which power ofsaid channel allocated to a signal subjected to received signal powermeasurement is higher than a predetermined value; and a step for settingsaid averaging section larger than the present averaging section whenperforming communication by a channel in each transmit power controlsection, in which power of said channel allocated to a signal subjectedto received signal power measurement is smaller than the predeterminedvalue.
 11. The received signal power measurement method as claimed inclaim 10, wherein said averaging section setting step comprises: a stepfor setting said averaging section larger than the present averagingsection when a partner transmit station transmits a channel whose poweris controlled and another channel whose power is not controlled with thesame antenna and directivity, and said channel whose transmit power isnot controlled transmits a pilot signal; and a step for setting saidaveraging section smaller than the present averaging section when apartner transmit station does not transmit said channel whose power iscontrolled and another channel whose power is not controlled with thesame antenna and directivity, or said channel whose transmit power isnot controlled does not transmit the pilot signal.
 12. The receivedsignal power measurement method as claimed in claim 10, wherein saidaveraging section setting step comprises: a step for detecting arelative traveling speed between a communication partner station and ownstation; and a step for setting said averaging section smaller than thepresent averaging section when said detected traveling speed is largerthan a predetermined value, and for setting said averaging sectionlarger than the present averaging section when said detected travelingspeed is smaller than the predetermined value.